/Engine/Plugins/Experimental/GeometryScripting/Source/GeometryScriptingCore/Public/GeometryScript/PolygonFunctions.h
Returns the specified vertex of a Polygon  either of the outer polygon, if HoleIndex is -1, or specified inner hole. Vertex will be the zero vector for invalid Polygon or Hole indices, or if the polygon is empty. VertexIndex will loop.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, Category="GeometryScript|PolygonList", Meta=(ScriptMethod)) static FVector2D GetPolygonVertex ( [FGeometryScriptGeneralPolygonList](API\Plugins\GeometryScriptingCore\GeometryScript\FGeometryScriptG-) PolygonList, bool & bIsValidVertex, int32 VertexIndex, int32 PolygonIndex, int32 HoleIndex )